That’s because in love, as with genies, we only get three wishes, says relationship expert Ty Tashiro. The more traits you pick that are above the average, the lower the statistical odds that you’ll find a match. And three is the tipping point.

Imagine you have a room of 100 men. If you choose mediocrity — the trifecta of average income, looks and height — you’ll have, statistically, only 13 suitors out of 100 to choose from. Increase your criteria to an attractive man at least 6-feet tall who makes $87,000, and you’re left with only one.

Add another trait — funny, kind, even a political affiliation — and it becomes statistically impossible to find him out of 100 men.

A study at the University of Tennessee, which recruited 82 newlyweds to rate each other’s attractiveness (to keep it honest they also had the research assistants rate their hotness factor), corroborates his conclusions. What they found was that there was “no relationship between either partner’s level of physical attractiveness and either partner’s relationship satisfaction.” The only significant association found was that the most physically attractive men were least satisfied with their marriages.

Agreeableness, one of the Big Five personality traits in the Five Factor Model of human psychology — the others being extroversion, conscientiousness, neuroticism and openness — describes someone who is “courteous, flexible, trusting, good-natured, cooperative, forgiving, soft-hearted and tolerant.”

Sure, it’s unsexy, but it’s the most reliable sign that your mate is a keeper for the long haul.

One study of 168 couples found that “the best variables for predicting who would stay married, even better than love, expressions of affection or negativity, was responsiveness, which is closely related to the trait of agreeableness,” Tashiro writes.

Plus, agreeable people are often better in bed.

“Men high in agreeableness are not only more likely to be kind, but also more likely to keep the sexual desire alive in relationships,” he writes. They are more giving and often more sensitive, which makes for better between-the-sheets action.

In other words, when looking for marriage material, nice guys should finish first. This is equally true for men looking for women: Niceness trumps all.